This proposal is an application to obtain a new multi-purpose multi-user flow cytometer, Becton Dickinson FACSCalibur with FL4 and sorting capabilities to provide adequate backup for the FACStar/PLUS. In addition, the following accessories are requested: FACSLoader and Barcode Scanner to increase the throughput of samples brought to the Cell Analysis (Facility). Increased sorting requests are over-committing the use of our FACStar/PLUS making it difficult to acquire data for routine immunofluorescent assays. In addition, any down time on the single flow cytometer available for research acquisition prevents results and unacceptable delays in acquisition. The primary users of the CAF have participated in this application and strongly support the request. An additional instrument for acquisition of multi-parametric data is needed to support ongoing studies and to facilitate research strategies for the successful competition for new and continuing NIH supported research at our institution. In addition, a benchtop flow cytometer such as the Becton Dickinson FACSCalibur would provide additional sorting time on the FACStar/Plus. Further, since both the FACStar/PLUS and the FACSCalibur utilize the same software for data collection and analysis, particularly the Becton Dickinson Attractors Program for multi-color analyses, retraining many of the users would be unnecessary. The researchers who will employ this instrument are supported by many NIH institutions and have an excellent record of prior and current funding. We also are acutely aware of the rapid growth of "high-tech" applications in modern basic and clinical research and expect to add additional NIH supported users to the user group. We encourage both NIH supported and scientists supported by other mechanisms to take advantage of the facility as time and availability permit in the interest of enhancing their potential for future NIH funding. The successful, but now overextended use of our current instrument has given us both the experience and desire to significantly upgrade our Core Facility. Administratively, the Flow Cytometry Advisory Committee, an experienced director, a well trained and experienced flow sorter operator, will allow rapid and efficient application of the new flow cytometer in ongoing and future projects.